In the aviation industry, the term aircraft performance mainly refers to the ability of the aircraft to operate safely under specific environmental and load conditions during the flight phases of take-off, landing and cruise. The aircraft performance mainly involves the calculation of a set of speeds and a corresponding power or thrust setting that will guarantee the safe operation of the aircraft during the different flight phases based on a set of input parameters such as the environmental conditions, the aircraft load and others. For example, for the take-off flight phase the aircraft performance may include among others the speed V1 of the aircraft at the point of decision during the take-off roll, the speed VR indicating the rotation speed of the aircraft on the runway, and the speed V2 indicating the speed of the aircraft after take-off. To enhance the accuracy of the aircraft performance and therefore the safety, the calculation may be supplemented with additional input parameters related to the aircraft configuration such as the flap and thrust or power settings. Therefore, the aircraft performance needs to be calculated not only with regards to the exact aircraft type but also taking into account the aircraft unique configuration settings in order to ensure the safe operation of the aircraft during the different flight phases. The aircraft performance calculations may be performed by the pilots or other highly trained personnel using a set of documents known as the pilot's flight bag. The pilot's flight bag includes, among other documents, the Aircraft Flight Manual (AFM) provided by the aircraft manufacturer, which details the recommended aircraft operating procedures for executing normal, abnormal and emergency operations during the different flight phases, together with the aircraft performance that should be achieved when the aircraft is operated in accordance with these procedures. In essence, the AFM provides a step-by-step guide with information indicating the parameters required to perform a given aircraft performance calculation, the associated documents, in either paper or digital format, containing the required parameters, and the calculation steps involved. To reduce the amount of paperwork carried in the aircraft cockpit the traditional pilot's flight bag is slowly being replaced with a digital version, known as the Electronic Flight Bag (EFB), which may be in the form of an electronic information management device to help flight crews perform flight management tasks more easily and efficiently, and with less paper.
The pilot calculates the aircraft performance based on the aircraft configuration and appropriate input parameters specified in the AFM so as to generate an aircraft performance profile indicating the set of speeds and the corresponding power or thrust setting for safely operating the aircraft for a given flight stage. The calculation may be performed manually or be automated, for example using the aircraft's flight management system (FMS) or a portable electronic device. For example, a SCAP module may be used for performing the aircraft performance calculation automatically. The SCAP (Standard Computerized Airplane Performance) is an IATA standardized method by which the aircraft manufacturers present their aircraft performance. The SCAP module takes two pre-defined vectors as inputs and returns two pre-defined vectors as output. In each case, one vector is alphanumeric and one is numeric. The SCAP module is generally written in a programming language known as FORTRAN. When called with a set of input parameters, the SCAP module returns either an error flag ‘A’ along with the resulting performance data or an error flag that is NOT ‘A’. In the case of a NOT ‘A’ return, the error flag can be either ‘B’ (Input error), ‘C’ (Computational error) or ‘E’ (Performance restrictions).
However, the above methods for calculating the aircraft performance either manually, using the AFM documents, or automatically, using the SCAP module, are greatly prone to human errors. For example, the pilot may enter in the SCAP module the wrong data for certain parameters, e.g. pressure, temperature or weight, thereby leading to an incorrect calculation of the aircraft performance. In another example, where the aircraft performance is calculated using the paper AFM procedure, the pilot may use the wrong performance charts for the aircraft type, select the wrong table or column/row in the performance charts, use incorrect values when referencing the performance charts, or fail to convert values into the required unit of measurement. Moreover, when considering that different airlines use, and different aircraft types require, different methods for calculating and entering aircraft performance parameters, it becomes very difficult to ensure that such errors are prevented or captured.
Furthermore, different airlines have different requirements for operating their aircrafts and may require that aircraft performance is calculated under different usage scenarios. For example, an airline may require that the aircraft performance is always optimised towards fuel efficiency irrespective of the weather conditions so as to reduce the operating cost of the aircraft. Such an optimisation may require the generation of a large number of aircraft performance profiles in a short amount of time, which may be performed by varying certain input parameters, so as to identify the aircraft performance that meets the optimisation goal set by the airline. Currently the performance calculating methods mentioned above are not suitable to handle the generation of multiple performance profiles in a short amount of time, since they require the user to input manually the input parameters and their subsequent variations for generating the different usage scenarios. Moreover, the SCAP module does not have the flexibility to accommodate the generation of different usage scenarios according to the airlines' requirements. This is because the SCAP module is a standalone module that is manufactured and provided by the original equipment manufacturer, meaning that its software code, after installation, is not accessible to the airline for modification. As a result, the airline has no control over the way the aircraft performance is calculated and the input parameters taken into account for such calculation, which may result in the aircraft being operated at a non-optimal aircraft performance leading to an increase in the aircraft operating costs in terms of maintenance and fuel consumption.
In M. Zontoul paper, “Rule based Aircraft Performance System”, presented at International Journal of Soft Computing and Engineering (IJSCE) in September 2013, an EFB software is provided for calculating the aircraft performance using the aircraft's Manufacturer Module (MM) e.g SCAP module. The user via the EFB device selects the required parameters from a global EFB database, which contains in addition to the performance parameters a set of rules indicating how the parameters can be combined together. Once the desired performance parameters are selected the EFB software communicates with the Manufactured Module (MM) via a predefined interface. The MM performs the calculation and the results are communicated to the EFB software for displaying to the user. A major limitation of the EFB software presented in this paper is that the user is still required to select the performance parameters, which as previously mentioned is human error prone and may lead to the incorrect calculation of the aircraft performance resulting in the unsafe operation of the aircraft. Moreover, the EFB software uses a Manufacturer Module (MM) for performing the calculations. As previously discussed, the MM offers limited flexibility in the way the aircraft performance is calculated and cannot accommodate the generation of different usage scenarios according to the airlines' requirements.